Needle-punched batting of polyester staple fibers



June 21, 1966 v. H. SCHEUERMAN 3,257,264

NEEDLE-PUNCHED BATTING OF POLYESTER STAPLE FIBERS Filed Oct. 10, 1965 Fl G 1 E mum on OTHER WED OPENED WEB OPENING DEVICE FIBER cnoss LAPPER Fl G. 2

INVENTOR VERNAL HARDY SCHEUERMAN BY M ATTORNEY United States Patent DNEEDLE-PUNCHED BATTING F POLYESTER STAPLE FIBERS Vernal HardyScheuerman, Wilmington, Del., assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware Filed Oct. 10,1963, Ser. No. 315,213 2 Claims. (Cl. 161-154) This invention relates tostufiing materials, particularly to needle-punched batts ofheavy-denier-per-filament polyester staple fibers and to a process forpreparing a needlepunched structure.

Needle-punching of loose batts of fibers is Well known to the art. Thefiber batts are needle-punched to impart to the batts the propertiesthat mechanical entangling and interlocking of fibers provide, and toincrease the strength of the batts. Needle-punching, as practiced by theart, has been concerned with uniformly compacted structures. It has nowbeen discovered that a unitary batt having nonuniform compactness can beprepared by needlepunching and that such structures are markedlysuperior to conventional structures for certain end-uses.

According to this invention, there is provided a process comprisingfeeding a loose fibrous batt of polyester staple fibers having a denierper filament of at least about 15, needling the batt so as to preventall of the barbs from completely penetrating the batt, to produce. aunitary stratified batt having a density of about 1.4 to about 2.9,preferably between 1.6 to 1.8 pounds per cubic foot.

The product of this invention is a unitary stratified batting highlysuitable as a cushioning material for upholstered furniture. The productconsists of two layers differing markedly in densityof the layers. Onelayer, comprising the major portion of the batt thickness, has a densityof about 1.8 to about 3.5, preferably between 2.8 and 3.0 pounds percubic foot. The other layer has a density of about 0.9 to about 1.5,preferably between 1.0 and 1.2 pounds per cubic foot. There is areasonably well-defined line of demarcation between the two layers and,while there is a slight density gradient Within the layers, the densitychanges Within each layer are small. As a consequence of thedual-density character of this product, it is markedly superior tocross-lapped batts and conventionally needled structures. The fibers ofthe dense layer of the batt are firmly locked together giving the batthigh dimensional stability and thus improving its ease of handlingcompared to the same material which has not been needle-punched. Moreimportantly, the dense layer provides the batt with the property ofeffectively masking the springs, edge wires, and the wooden frames,etc., of upholstered furniture, while the non-needled structure shiftsat stress-points. The low density layer provides surface softness andloft. The loft, or filling power, of the low density layer permits thecushions and backs etc., of upholstered furniture to be filled with aminimum 'of material while providing the full, luxuriousappearancerequired for upholstered furniture. Further, the dual nature of thesebatts provide optimum compressibility and resilience since the battcompresses readily under force, but with increasing resistance. Thus,these batts have neither the harsh,'boardy feel resulting from a highdensity structure, nor the soft, mushy feel of a low-density product.

In accordance with the process of this invention, the batts justdescribed are prepared by a single pass of a batt of loose fibersthrough a needle loom. The unitary nature of the dual-density batts ishighly advantageous, it being neither necessary nor desirable to preparea com posite structure of two or more elements. In addition, nosupporting or reinforcing element is required; i.e., the use of achemical bonding agent or a backing such as cheesecloth or burlap, tostrengthen or to provide a base to which the fibers are locked, is notneeded.

Patented June 21, 1966 The batting of this invention may be constructedof any suitable staple fiber such as those of polyacrylonitrile,polyester, rayon, and nylon. The most useful products are obtained whenpolyester staple fibers are employed, as polyester fibers are highlyresilient and unaffected by moisture.

The staple fibers range in length from about 2 to about 6 inches;preferably, the fiber length is from 2 to 4.5 inches. It is necessarythat the staple fibers be crimped for optimum interlocking of thefibers. The fiber crimp should be between 2 and 15 crimps per inch;preferably, the fibers have between 4 and 10 crimps per inch.

In order to obtain the product of this invention, it has been found,surprisingly, that the stable fibers must have a denier per filament ofat least about 15. Low deniers of about 5.0 denier per filament arenotsuitable for the practice of this invention. Loose fibrous batts of lowdenier-per-filament fibers are not readily converted to dual-densitystructures by needle-punching, and, where a dual-density structure isachieved by using relatively high needle penetrations, they do notapproach the required density range. Deniers greater than about 75 aredifficult to produce economically because of quenching problemsassociated with their manufacture and, further, are diflicult to crimp.Therefore, in practicing this invention it is preferred to use fibershaving a denier per filament of about 15 to 75 and more preferablybetween 25 and 45.

The loose fiber batts used in the practice of this invention areprepared in any suitable manner. For example, the fibers may be passedthrough a garnet or card and the resulting web cross-lapped to thedesired thickness in a manner known to the art. Alternatively, they maybe produced by depositing the fibers from a fluid stream onto a suitablesupport suchas a screen. When using a garnet, the web is cross-lappedto'give a batting weight of 9 to 40preferably, 13 to 36--ounces persquare yard. Due to the inherent characteristics of garnet operation,these batts have a density of about 0.7 to 0.8 for all fiber deniers.

The batting is then sent one pass through' a needle loom fitted with aplurality of conventional-barb needles. The number of needles in theneedle board, the frequency of the reciprocating stroke, and the advanceof the batting through the needle loom are adjusted to give about 10 toabout 80, preferably 20 to 40 penetrations per square inch. The numberof penetrations per inch is dependent on the denier per filament of thefibers. In general, the higher the denier per filament of. fibers, the

lower will be the penetrations per inch in order to obtain products withthe optimum density characteristics. For example, a loose battconsisting of fibers having a denier per filament of 37 gives astructure whose properties are mediocre at penetrations per square inchand a highly unsuitable structure at the relatively high'level ofpenetrations per square inch. In comparison, a loose batt of 18 denierper filament fibers gives an unacceptable structure at 30 penetrationsper square inch and an excellent structure at about 80 penetrations persquare inch.

The depth of needle penetration is critical. It is essential that theneedle be inserted into the loose fiber batt so that not all of thebarbs, and preferably less than one-half of the barbs, of the needlepass all the way through the batt. Excessive penetration of the barbs ofthe needle results in the loss of the dual-density characteristic of thebatts of this invention.

In the drawings, which illustrate specific embodiments of the invention,

FIGURE 1 is a diagrammatic representation of the process described abovewherein baled staple fibers are opened into a web, cross-lapped to forma loose batt of the desired weight and fed through a needle loom to formthe stratified batting of this invention. The needle Example IPolyethylene terephthalate staple fibers having a length of 3 inches andabout 5 c-rimps per inch and the denier shown in Table I are passedthrough a garnet and crosslapped to a batt thickness of about 4 inches.The loose fibrous batts thus prepared are then given one pass through aneedle loom so as to give about 30 penetrations per square inch. Theneedles have a -gauge shank, an IS-gauge step-down, and a -gauge blade.The blade is of equilateral triangular cross-section. Each of the threeedges of the blade has three notched barbs. The first barb is 0.25 inchfrom the tip of the blade, and the restv of the barbs are so staggeredthat there is one barb every 0.083 inch further up the blade. Thus, ifthe needle is vdriven into the batt so that 1 inch protrudes, the barbfurthermost from the tip will have just penetrated through the batt. Inthis example, needle penetration is adjusted so that 0.35 inch of theneedle blade protrudes from the batt. The resulting batts have thecharacteristics shown in Table I. 1

TABLE I Denier .I 4. l 18 28 37 Density, lbs/cu. lt.:

Batt 0. 83 1. 21 1. 59 2. 38 Lower Layer (1) 0. 86 1. 12 1. 18 UpperLayer 1. 50 1. 90 d. 18

1 One layer.

The lower layer designation used in Table I refers to the layercontaining the surface through which the needle protrudes, the upperlayer containing the surface first penetrated by the needles.

Example II Example I is repeatedexcept that the batts are needled togive penetrations per square inch. The density values for the resultingbatts are given in Table II.

TABLE II Denieru 4. 75 1s 2s 37 Density, lbs/cu. it;

a 0. S9 1. 75 2. 22 2. 92 Lower Layer 0.75 1. 04 1. 26 1. 46 UpperLayer 1. 10 2. 25 2. 65 0'. 336

Example Ill Example I is repeated except that the batts are needled sothat 0.75 inch of the needle blade protrudes from the batt. Theresulting batts have a relatively uniform density with no indication oftwo layers.

Polyesters suitable for the practice of this invention are thosecrystallizable linear condensation polymers containing in the polymerchain carbonyloxy-linking radicals,

Polymers containing oxycarbonyloxy radicals are comprehended within thisgroup. The polymers should be of fiber-forming molecular weight.Copolyesters, terpolyesters, and the like, are intended to becomprehended within the term polyesters.

Examples of crystallizable, linear condensation polyesters includepolyethylene, terephthalate, polyethylene terephthalate/isophthalate(/15), polyethylene terephthalate/hexahydroterephthalate (/10),polyethylene terephthalate/S-(sodium sulfo)isophthalate (97/3), poly-(p-hexahydroxylene terephthalate), poly(diphenylolpropane isophthalate),poly(diphenylolpropane carbonate), the polyethylene naphthalenedicarboxylates (especially those derived from the 26 and 27-isomers) andpoly- (m-phenylene isophthalate), as well as many others.

The heavy denier-per-filarnent product of this invention, in addition tobeing highly suitable for use as a cushioning material in upholsteredfurniture, is also useful in the manufacture of pads to be used asdomestic or industrial scouring and polishing materials. Such scouringand polishing materials are prepared by impregnating and/or coating oneor both sides of the dual density webs with a water-insoluble resinousmaterial, in the form of a latex, dispersion, or solution, with orwithout abrasive particles.

Since many different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof, it is to be understood thatthe invention is not limited to the specific illustrations except to theextent defined in the following claims.

. I claim: a

1. A unitary stratified batting, suita le for use in upholsteredfurniture; of crystallizable, linear condensation polyester staplefibers having a denier per filament of 15 to 75, a fiber length of 2 to6 inches, and between 2 and 15 crimps per inch of fiber; the battinghaving a density within the range of 1.4 to 2.9 pounds per cubic foot,the major portion of the batt thickness being a substantially uniformlayer having a higher density within the range of 1.8 to 3.5 pounds percubic foot, and the higher density layer being unitary with asubstantially uniform layer having a lower density within the range of0.9 to 1.5 pounds per cubic foot; the fibers being entangled throughoutthe batting and invidual fibers being oriented in a positionsubstantially perpendicular to the face of the batting through saidhigher density layer and extending into the lower density layer.

2. A unitary stratified batting for upholstery use of linearcondensation ethylene terephthalate polyester staple fibers having adenier per filament of 25 to 45, a fiber length of 2 to 4.5 inches, andbetween 4 and 10 crirnps per inch of fiber; the "ba ting having adensity within the range of 1.6 to 1.8 pounds per cubic foot andconsisting of two layers, a layer of substantially uniform higherdensity within the range of 2.8 to 3.0 pounds per cubic foot and a layerof substantially uniform lower density within the range of 1.0 to 1.2pounds per cubic foot; the fibers being entangled throughout the battingand individual fibers being oriented in a position substantiallyperpendicular to the face of the batting, through said higher densitylayer and extending into the lower density layer, to provide a unitarystructure.

References Cited by the Examiner UNITED STATES PATENTS 2,978,785 4/1961VVenzell et al 16l154 X 3,112,552 12/1963 Smith 16l154 X 3,171,1513/1965 Sickle et al. 161-154 X ALEXANDER WYMAN, Primary Examiner.

MORRIS SUSSMAN, Examiner.

1. A UNITARY STRATIFIED BATTING SUITABLE FOR USE IN UPHOLSTEREDFURNITURE; OF CRYSTALIZABLE, LINEAR CONDENSATION POLYESTER STAPLE FIBERSHAVING A DENIER PER FILAMENT OF 15 TO 75, A FIBER LENGTH OF 2 TO 6INCHES, AND BETWEEN 2 AND 15 CRIMPS PER INCH OF FIBER; THE BATTINGHAVING A DENSITY WITHIN THE RANGE OF 1.4 TO 2.9 POUNDS PER CUBIC FOOT,THE MAJOR PORTION OF THE BATT THICKNESS BEING A SUBSTANTIALLY UNIFORMLAYER HAVING A HIGHER DENSITY WITHIN THE RANGE OF 1.8 TO 3.5 POUNDS PERCUBIC FOOT, AND THE HIGHER DENSITY LAYER BEING UNITARY WITH ASUBSTANTIALLY UNIFORM LAYER HAVING A LOWER DENSITY WITHIN THE RANGE OF0.9 TO 1.5 POUNDS PER CUBIC FOOT; THE FIBERS BEING ENTANGLED THROUGHOUTTHE BATTING AND INVIDUAL FIBERS BEING ORIENTED IN A POSITIONSUBSTANTIALLY PERPENDICULAR TO THE FACE OF THE BATTING THROUGH SAIDHIGHER DENSITY LAYER AND EXTENDING INTO THE LOWER DENSITY LAYER.